Billy Bob Thornton is an American actor, filmmaker, singer, and musician who has worked extensively in live-action film and television. His career includes a single, well-known contribution to the field of anime voice acting. While he has voiced characters for other animated projects, his work in the specific genre of Japanese animation, or anime, is limited to one prominent role.

Thornton provided the English dub voice for the character Jigo in the Studio Ghibli film Princess Mononoke. The film was originally released in Japan in 1997, with the English-dubbed version produced by Miramax Films and released in 1999. In this production, Thornton voiced the character of Jigo, a crafty and morally ambiguous monk or priest. Jigo initially appears as an ally to the film's protagonist, Ashitaka, offering him guidance. However, it is later revealed that Jigo is a mercenary who has been contracted by the emperor to obtain the head of the Forest Spirit, a powerful god, making him a secondary antagonist in the story. The English adaptation of Princess Mononoke featured a cast of well-known American actors, including Billy Crudup, Claire Danes, Minnie Driver, and Gillian Anderson, alongside Thornton.

Beyond this performance, Billy Bob Thornton does not have a broader filmography as an anime voice actor. His other voice work includes roles in American animated productions, such as the character Jack in the DreamWorks film Puss in Boots. He has also made guest voice appearances on American television series like King of the Hill and Robot Chicken. However, he has not taken on additional roles in Japanese animation or established recurring collaborations with anime studios, directors, or voice directors. As a result, his significant achievement in this specific field remains his performance in Princess Mononoke, which is notable for being part of a landmark film from Hayao Miyazaki and Studio Ghibli, one of the most celebrated studios in animation history.